Combination conductor-antenna

ABSTRACT

A combination conductor-antenna apparatus is provided comprising a surface that defines a passage for use as a receptor for a second conductor and for use as a waveguide. The surface is at least partially formed of an electrically conductive material, thus allowing the apparatus to serve as a medium by which an electrical signal can be transferred from a second conductor. Disposed within the passage is a pickup element for sensing and/or injecting electromagnetic energy in the passage, thus allowing the apparatus to serve as a medium for wireless communications.

This is a divisional of co-pending application Ser. No. 10/742,670,entitled “Combination Conductor-Antenna” by inventors Williams, Bakerand Schroeder, filed on Dec. 19, 2003, for which the earlier effectivefiling date is hereby claimed.

FIELD OF THE INVENTION

This invention relates to a combined antenna and conductor, such as acontact element that serves as a combination conductor and waveguideantenna and/or a connector having such a contact element.

SUMMARY OF THE INVENTION

According to the present invention, a contact element is provided thatcan serve as both an electrical socket for direct-contact communicationsand can serve as a waveguide antenna for wireless communications. Thecontact element includes a surface extending in a longitudinaldirection, the surface defining a passage that extends between anopening at a first end of the contact element and a back wall at asecond end of the contact element. The contact element also includes apickup element for injecting and/or sensing electromagnetic energy inthe passage. The pickup element extends into the passage from thesurface in a direction normal to the surface.

It is preferable that at least a portion of the surface be electricallyconductive in order to allow for the contact element to providedirect-contact communication. The surface can include a contactingsection that is electrically conductive and extends from the openingtowards the back wall. The surface can also include a pickup sectionthat is electrically conductive and extends from the back wall towardsthe opening. In such a case, the pickup element can extend from thepickup section of the surface. The surface can further include aninsulating section between the contacting section and the pickup sectionfor electrically isolating the contacting section and the pickup sectionfrom each other.

The surface can optionally be shaped so as to provide for modeconversion, for example to convert circular mode electromagnetic wavesentering the opening into rectangular mode waves.

A distance d between the pickup element and the back wall can preferablybe selected to satisfy the following relationship:d=¼λ _(g)=¼(λ_(o)/(1−(λ_(o)/λ_(c))²)^(1/2))

where λ_(g) is a wavelength of an operating frequency of the contactelement (i.e., waveguide wavelength), λ_(c) is a lower dominant modecutoff wavelength of the operating frequency, and λ_(o) is a wavelengthof the operating frequency in free space.

The opening in the contact element can be circular and have a radius rthat satisfies the following equation:r=λ _(c) /k

where λ_(c) is a lower dominant mode cutoff wavelength of an operatingfrequency of the contact element and k is a constant associated with anoperating mode of the contact element.

According to another aspect of the invention, a connector assembly isprovided that includes a support member and a contact element, supportedby the support member, for mating with a pin element of an opposingconnector and for serving as a waveguide for transmitting and/orreceiving wireless communication.

The contact element can include a surface that extends in a longitudinaldirection, defining a passage that extends between an opening at a firstend of the contact element and a back wall at a second end of thecontact element. The contact element can further include a pickupelement for injecting and/or sensing electromagnetic energy in thepassage, the pickup element extending into the passage from the surfacein a direction normal to the surface.

The connector assembly can further include a second contact element,supported by the support member, for mating with a second pin element ofan opposing connector, wherein the second contact element is incapableof serving as a waveguide for transmitting and/or receiving wirelesscommunication.

According to another aspect of the invention, a projectile is providedthat includes a connector having a contact element for mating with a pinelement of an opposing connector in order to transfer electrical signalsfrom the pin element and for serving as a waveguide for receivingwireless communication signals. The projectile also includes a receiverin communication with the contact element for converting the receivedwireless communication signals into data signals, and a data processorin communication with the contact element for receiving from the contactelement the electrical signals transferred from the pin element.

According to another aspect of the invention, a projectile controlsystem is provided that includes a projectile having a projectileconnector that includes a contact element, a pre-launch controller forcommunicating with the projectile prior to a launch of the projectile,an umbilical cord for electrically connecting the contact element of theconnector to the pre-launch controller, and a transmitting device forwirelessly communicating with the projectile via the contact element ofthe connector after the launch of the projectile.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and is notlimited by the figures of the accompanying drawings, in which likereference numbers indicate similar parts:

FIG. 1 shows a perspective view of a contact element according to afirst embodiment of the present invention;

FIG. 2 shows a partially cut-away view of the contact element shown inFIG. 1;

FIGS. 3A and 3B show examples of connectors that can be used inconjunction with the contact element of the present invention;

FIG. 4 shows field lines associated with various waveguide modes;

FIG. 5 shows a geometry that can be used for the contact element of thepresent invention;

FIGS. 6-9 show plots of antenna power patterns associated withrespective variations of the present invention;

FIG. 10 shows a perspective view of a contact element according to asecond embodiment of the present invention;

FIG. 11 shows a partially cut-away view of the contact element shown inFIG. 10;

FIG. 12 shows a partially cut-away view of a contact element accordingto a third embodiment of the present invention;

FIG. 13 shows a perspective view of a connector assembly for use withone or more contact elements of the present invention;

FIG. 14 shows a perspective view of the connector assembly shown in FIG.13 aligned with a plug assembly;

FIG. 15 shows a plan view of the connector assembly shown in FIG. 13;

FIG. 16 shows a cross-sectional view taken along lines XVI-XVI shown inFIG. 15;

FIG. 17 shows a projectile utilizing the contact element of the presentinvention in a pre-launch configuration;

FIG. 18A shows the projectile of FIG. 17 in a post-launch configuration;

FIG. 18B shows a plan view of the base of the projectile of FIG. 18A;and

FIG. 19 shows a block diagram of the projectile of FIG. 17.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a perspective view of a contact element 100 in accordancewith a first embodiment of the invention. FIG. 2 shows a partiallycut-away view of the contact element 100. The contact element 100 can beused as a socket contact in a connector, such as those shown in FIGS. 3Aand 3B. Each of the connectors 150 and 155 have a plurality of sockets160, any one or more of which can be populated with the contact element100. The connectors 150 and 155 are shown for exemplary purposes only,and are in no way intended to limit the scope of the invention.

The contact element 100 allows for both direct-contact and contactlessforms of communication. For example, the contact element 100 can providefor direct-contact communication in the form of an electrical signalsuch as a DC voltage and can provide for contactless communication inthe form of electromagnetic waves. This is accomplished by providing thecontact element 100 with a contacting section 110 for direct-contactcommunication and a pick-up section 115 for contactless, or wireless,communication. This allows a connector having the contact element 100 toserve as both a direct-contact connector and an antenna.

For direct-contact communication, a pin contact 140 (shown in phantom)can be inserted into the contact element 100 through opening 105. Thecontacting section 110 has an inner surface made of a conductivematerial, for example copper, silver, or gold, allowing signals to betransferred between the contact element 100 and a pin contact that hasbeen properly inserted. A contact signal line 135 provides a signal pathto and from the contacting section 110, bypassing the pick-up section115. In addition, an insulating section 125 is provided for electricallyisolating the contacting section 110 from the pick-up section 115. Thus,the pin contact 140 should be selected such that it does not extendbeyond the insulating section 125 when inserted into the contact element100.

For contactless or wireless communications, the contact element 100 canserve as a cylindrical waveguide, where the opening 105 is the waveguideaperture. A probe 120 is provided in the pick-up section 115 forabsorbing and/or injecting electromagnetic energy in the contact element100. The inner surface of the pick-up section 115, including a back wall130, is made of a conductive material, for example copper, silver orgold.

Thus, at times when there is no pin contact inserted in the contactelement 100, the contact element 100 is open and can serve as acircularly polarized antenna. Apertures like antennas act as high-passfilters with a cutoff wavelength set by dimensions of the aperture,which in the first embodiment is the opening 105. In the case ofcircular apertures, the cutoff wavelength differs for different modes ofoperation, where a “mode” refers to the shape and structure ofelectromagnetic field-lines carried within the waveguide once the fieldhas passed into the waveguide from its associated aperture. The dominantmode in a circular waveguide is a transverse electric (TE) mode known asTE₁₁, shown in FIG. 4. Other modes possible with a circular waveguideinclude TE₀₁, also shown in FIG. 4, and a transverse magnetic (TM) modeknown as TM₀₁. Circular cutoff wavelengths λ_(c) are dependent upon aproduct of a radius of the waveguide opening and a constant k, whichvaries among different modes. For example, for TE₁₁, TE₀₁, and TM₀₁modes the constants are shown in Table 1 below (where r is radius).

TABLE 1 TM₀₁ TE₁₁ TE₀₁ k 2.61 3.412 1.640

Thus, the size (inner diameter) of the opening 105 has an impact oncutoff and allowed mode. For example, the cutoff wavelength λ_(c) for acircular waveguide for TE₁₁ mode is λ_(c)=(k)(r)=(3.412)(r). If thecutoff frequency λ_(c) for this mode is set at 30 GHz, r is found to ber₃₀=0.293 cm (solving for r=λ_(c)/3.412=(c/30 GHz)/3.412, where c=speedof light), or in inches, r₃₀=0.12 in. If the cutoff frequency λ_(c) forthis mode is set at 90 GHz, r is found to be r₉₀=0.088 cm, or in inches,r₉₀=0.035 in.

The shape of the contact element of the present invention can vary froma cylinder. For example, the shape of the contact element can vary inorder to allow for mode conversion. Methods of designing waveguides tocause a specified mode conversion are known in the art. However, sincethe contact element of the present invention can serve as both a socketfor mating with a pin contact and a waveguide for wirelesscommunication, the shape of the contact element is preferably selectedto allow for at least a portion of the inner side of the contact elementnearest the opening to make contact with an inserted pin contact. As anexample, in FIG. 5 a geometry is shown that can be implemented as analternative shape for the contact element 100. The geometry shown inFIG. 5 extends in a longitudinal direction and has an opening at one endthereof, a back wall at the other end thereof, and a surface thatdefines an inner passage extending between the opening and the backwall. Beginning at the opening, a first portion of the surface iscylindrical and has a constant diameter, a second portion of the surfaceis cylindrical and has a gradually increasing diameter, a third portionof the surface is cylindrical and has a gradually decreasing diameter, aforth portion of the surface is a gradual transition from a cylindricalshape to a rectangular shape while the diameter continues to graduallydecrease, and a fifth portion of the surface has a rectangularcross-section having a constant size. Since the first portion of thesurface has a constant diameter, a portion of the inner side of thecontact element nearest the opening can make contact with a cylindricalpin contact. The geometry shown in FIG. 5 also provides for convertingcircular TE₀₁ waves to rectangular TE₂₀ waves and for convertingcircular TE₁₁ waves to rectangular TE₁₀ waves. FIG. 4 shows the electricfield lines for each of these modes.

The insulating section 125 is made of a dielectric insulating materialsuitable for protecting the pick-up section 115 from data voltage. Sincethe inner surface of the insulating section 125 is an insulatingmaterial rather than a conductive material, the insulating section 125interrupts the internal waveguide field by providing a section throughwhich the wave must travel via free space. The desirable length of thissection (i.e., distance between respective inner surfaces of contactingsection and pickup section) is determined based on the breakdown voltage(dielectric breakdown) of the material used to create the insulatingsection 125. Table 2 below shows examples of dielectric strengths forsome common materials that can be used for the insulating section 125.

TABLE 2 Material Dielectric Constant Dielectric Strength (V/m) Air 1.0 3 × 10⁶ Paper 2-4 15 × 10⁶ Polystyrene 2.6 20 × 10⁶ Rubber 2.3-4.0 25 ×10⁶ Glass  4-10  3 × 10⁶ Mica 6.0 200 × 10⁶ 

In the present embodiment, rubber is used as an easily manufacturedinsulating section 125 between the contacting section 110 and thepick-up section 115 and a data-line voltage of 5 volts. Using the datafrom Table 2, the thickness of the insulation section can be calculatedas (5V)/(25×10⁶ V/m)=200×10⁻⁹ m. However, this only accounts for thedielectric strength of the material used for the insulating section 125.Since air, especially near saltwater, has a lower dielectric strength,the spacing requirement between the respective outer surfaces of thecontacting section 110 and the pick-up section 115 is increased. Wheresalt-air is a factor of 100× lower in dielectric strength than “air” (asnoted in Table 2) the rubber insulating section 125 would have to be(5V)/(10⁻²×3×10⁶)=0.17 mm thick. Where salt-air is a factor of 1000×lower, the rubber insulation section would have to be(5V)/(10⁻³×3×10⁶)=1.7 mm thick.

However, the distance between the exposed portions (i.e., exposed toair) of the contacting section 110 and the pick-up section 115 need notbe equal to the distance between the unexposed conductive surfaces ofthe contacting section 110 and the pick-up section 115. For example, asshown in FIG. 2, the insulating section 125 can be configured such thatonly part of the insulating section 125 actually interposes thecontacting section 110 and the pick-up section 115, and the rest of theinsulating section is wrapped around the exterior of the contact element100. This configuration allows for adequate spacing between conductiveouter surfaces while reducing the distance a wave must travel via freespace within the contact element. It should be noted that, while FIG. 2shows the insulation wrapping around the exterior of both the contactingsection 110 and the pick-up section 115, the insulation wrapping can,instead, be positioned around the exterior of only one of the contactingsection 110 or the pick-up section 115 and still be sized to provide anadequate distance between the respective outer surfaces.

To maximize RF absorption, it is desirable to optimize the placement ofthe probe 120 in the pick-up section 115. The optimal location for thepresent embodiment is determined considering a plane wave incidentnormally on a perfect plane conductor—similar to the condition of theback wall 130 in the contact element 100. An E-field incident on a planeconductor such as the back wall 130 experiences a 180° phase shift uponreflection. Mathematically, this is to satisfy the boundary conditionthat an electric field goes to zero on the surface of an idealconductor. Intuitively, this may be seen as an electron response tobeing pushed in one direction at some instant, creating a reverseelectromotive force (or field) effect in the opposite direction.

The incident and reflected waves produce a standing wave within thecavity of the contact element 100. The 180° phase shift noted abovemoves the location of maxima and minima field strength within thecavity. Avoiding a minimum of zero field—due to interference betweenincoming and outgoing waves—at ¼ wavelength from the back wall 130, amaximum wave energy can be found. By this simplified treatment, theprobe 120 can be placed ¼ of a waveguide wavelength from the back wall130.

However, under certain conditions, locating an optimal position for theprobe 120 may not be so simple. For example, in the case of arectangular waveguide or rectangular transition in a waveguide, thefield reflects down the waveguide, off sides of the waveguide at someangle set by guide size and frequency. Phase change of reflectedE-fields depends upon E-polarization with respect to the plane ofincidence. The plane of incidence is defined as that plane containingboth incident and reflected beams in a plane normal to the surface. Forpolarization perpendicular to the incident plane, the same 180° phaseshift mentioned above occurs when the index of refraction in a mediumthe beam is from is lower than that of the medium of the incident plane.In the present embodiment, the index of refraction can be consideredinfinite as for a perfect conductor. Further analysis shows thatdielectric/conductor interfaces behave the same for parallelpolarization as for perpendicular polarization in terms of a phaseshift. This equality in phase behavior for both polarizations means thatit is not necessary to know the plane of incidence in the event oflinear transmissions from a ground source. As a result, no matter whatthe orientation of the contact element 100, the probe 120 remains ¼waveguide wavelength from the back wall 130. Optimal distance d from theback wall 130 is therefore:d=¼λ_(g)=¼(λ_(o)/(1−(λ_(o)/λ_(c))²)^(1/2))   (1)where λ_(g) is the wavelength of an electromagnetic wave within thewaveguide, λ_(c) is the lower dominant mode cutoff wavelength, and λ_(o)is the wavelength of electromagnetic wave in free space, i.e., thefree-space frequency. For example, in the case of Ka band, thefree-space frequency is f_(o)=35 GHz and the cutoff frequency can bef_(c)=30 GHz, so (using c=3×10⁶ m/s) the distance from the back wall 130to the probe 120 is then ¼λ_(g)=¼(0.86 cm/(1−(0.86 cm/1.0cm)²)^(1/2))=0.42 cm. As another example, in the case of W band, thefree-space frequency is f_(o)=94 GHz and the cutoff frequency can bef_(c)=90 GHz, so (using c=3×10⁶ m/s) the distance from the back wall 130to the probe 120 is then ¼λ_(g)=¼(0.316 cm/(1−(0.316 cm/0.33cm)²)^(1/2))=0.28 cm.

The length of the waveguide (from opening 105 to back wall 130) can beset to take advantage of the tendency of a beamwidth to narrow withsidelobes settling out once the length to diameter (of the waveguide)ratio is slightly greater than 4. Thus, in the examples from above forKa band, having a cutoff frequency of 30 GHz (r₃₀=0.293 cm so d₃₀=0.586cm), or for W band, having a cutoff frequency of 90 GHz (r₉₀=0.088 cm sod₉₀=0.176 cm), the length of the waveguide can be approximately:Waveguide Length₃₅=2.344 cmWaveguide Length₉₄=0.704 cm

As noted above, more than one connector socket can be populated with thecontact element 100. Since the contact element 100 is such a relativelysmall element, it tends to behave much like an ideal, elemental,isotropic Huygens wavelet source, so a phased array approach can be usedto narrow the combined beamwidth. Examples discussed below and shown inFIGS. 6-9 illustrate results of adding an array of contact elements 100.

Numerical comparisons between FIGS. 6 and 7 (both 35 GHz plots) showimprovement in beam shaping when an array of contact elements is used.In FIG. 6, a plot is shown for a single contact element 100, whichpresents a beamwidth of 100° and 72° for E and H planes, respectively.On the other hand, FIG. 7 shows a plot for an array of 9 pins, whichpresent a pattern of 68° beamwidth for both E and H planes. Numericalcomparisons between FIGS. 8 and 9 also show improvement in beam shapingfor an array of contact elements 100 as opposed to a single contactelement 100, where beamwidth is reduced from E=156° and H=76° to 18°with sidelobes at −13 dB at 30° off boresight. Thus, arrangement of thecontact elements 100 in a connector can be selected to suit desiredbeamwidth and sidelobe characteristics.

Turning now to FIGS. 10 and 11, a contact element 200 is shown inaccordance with a second embodiment of the present invention. Thecontact element 200 differs from the contact element 100 of the firstembodiment in that the contact element 200 has no insulating section,but instead has a combined contacting/pick-up section 210.

The contact element 200 can be used for direct-contact and wirelesscommunication. The contact element 200 is preferably constructedprimarily of a highly conductive material. Examples of suitablematerials include copper, silver, and gold. The contact element 200 hasan opening 205 for accommodating the insertion of a pin 240 (shown inphantom). Direct-contact communication can then take place between thecontact element 200 and the pin 240, which are in contact with eachother allowing for the direct transfer of signals, which can betransferred from the contact element 200 via a contact signal line 235.The contact element 200 also has a probe 220 for injecting and/orabsorbing electromagnetic energy in the contact element 200. A probesignal line 245 is provided to transfer signals to and from the probe220. As described above for the first embodiment, the inner chamber ofthe contact element 200 from the opening 205 to the back wall 230 actsas a waveguide, particularly when there is no pin 240 present. While thecontact element 200 of the second embodiment eliminates the insulatingsection 125 of the first embodiment, it is still necessary to ensurethat the pin 240 is not too long. That is, the pin 240 should beselected such that it will not damage the probe 220 when inserted in thecontact element 200.

The manner in which the contact element 200 can be configured (i.e.,length, diameter, probe placement, shape variation) with considerationto its function as a waveguide is essentially the same as describedabove with respect to the first embodiment, and for this reason suchdescription is not repeated here. However, it is worth noting that thecontact element 200 represents a much more simplified constructioncompared to that of contact element 100 since the contact element 200does not require the insulating section 125.

Turning now to FIG. 12, a third embodiment of the present invention isshown. In the third embodiment, a probe signal line 255 is used in placeof both the probe signal line 245 and the contact signal line 235 of thesecond embodiment. The probe signal line 255 is a multi-layer signalline having alternating layers of conductors and insulators. Forexample, the probe signal line 255 can be a shielded coaxial cable. Asshown in FIG. 12, the probe signal line includes an outer insulatinglayer 260, an outer conducting layer 265, an inner insulating layer 270,and an inner conductor, which in this case is the probe 220. The probe220 is insulated from the conductive surface of the contact element 200by the inner insulating layer 270. On the other hand, the outerconducting layer 265 is in contact with the conductive surface of thecontact element 200. Therefore, the outer conducting layer 265 can beused to transfer direct-contact signals to and from the contact element200 in place of a separate contact signal line 235.

Turning now to FIGS. 13-16, an example of a connector assembly 300populated with contact elements of the present invention will bediscussed. The connector assembly 300 includes a plurality of contactelements 200 according to the second embodiment. The connector assemblyis also populated with a plurality of contact elements 310, which aredesigned to be used only for direct-contact (i.e., contact elements 310have no probe 220). The connector assembly 300 includes a support member320, which is constructed of an insulating material such as rubber orplastic. The support member 320 aids in maintaining the spacing andorientation of the contact elements 200 and 310. It will be appreciatedthat the connector assembly can be equipped with additional connectorhardware not shown including a backshell, shield, strain relief, hood,receptacle plate, coupling ring or collar. It will also be appreciatedthat any embodiment of the contact elements of the present invention canbe used in the connector assembly 300.

FIG. 14 shows a perspective view of the connector assembly 300 withoutthe support member 320. FIG. 14 also shows a plug assembly 330 alignedwith the connector assembly 300 for connection therewith. FIG. 15 showsa plan view of the connector assembly 300, providing a direct view intothe contact elements 200 and 310. FIG. 16 shows a cross-sectional viewthe connector assembly 300 along section XVI-XVI shown in FIG. 15.

The plug assembly 330 is populated with a plurality of pins 240 forproviding direct-contact communication with respective contact elements200/310 when connected. Thus, it will be appreciated that the contactelements 200 of the connector assembly 300 serve a dual purpose byproviding both direct-contact communication and wireless communication.That is, when the connector assembly 300 is connected to the plugassembly 330, the contact elements serve as a conduit for direct-contactcommunication with pins of the plug assembly 330. On the other hand,when the connector assembly 300 is not connected to the plug assembly330, the contact elements 200 are free to act as waveguides.

From the view shown in FIG. 15, it can be seen that each of the contactelements 200 is provided with a respective probe 220, probe signal line245, and contact signal line 235, while each of the contact elements 310is provided with only a respective contact signal line 235. As shown inFIG. 16, the probe signal line 245 can be a cable having a solid centerconductor that extends into the contact element 200 to serve as theprobe. On the other hand, it is contemplated that the contact element200 can be fitted with a separate element, such as a pin or the like, toserve as the probe 220, or the probe 220 can be integrally formed withthe body of the contact element 200, in which cases the probe signalline 245 could be connected or attached to the contact element 200 suchthat the center conductor of the probe signal line is in communicationwith the probe 220.

It will also be noted that, in the configuration shown in FIG. 15, thecontact elements 200 populate all of the outer positions of theconnector assembly 300, while the contact elements 310 populate all ofthe inner positions of the connector assembly 300. However, thisconfiguration is shown only as an example of a connector populated withthe contact elements 200 in combination with other types of contactelements, and is no way intended to limit the scope of the presentinvention. Rather, as discussed above, the arrangement of and number ofcontact elements 200 can be varied to satisfy design requirements. Forexample, it is contemplated that a connector assembly in accordance withthe present invention can be a single or multi-contact connector havingone or more contact elements 200 in combination with none of the contactelements 310 or in combination with one or more of the contact elements310.

There are numerous applications that would benefit from the use of aconnector that can serve to provide both wireless and direct-contacttypes of communications. One such application is in the field of guidedprojectiles as illustrated in FIGS. 17-19. FIG. 17 shows a projectile400 in a pre-launch configuration, FIG. 18A shows the projectile 400after launch, FIG. 18B is a plan view of the base of the projectile 400during flight, and FIG. 19 shows a block diagram of the control systemwithin the projectile 400.

Prior to launch, the projectile 400 is connected to a pre-launchcontroller 410 via an umbilical cord 420. The umbilical cord 420 isattached to a projectile connector 440 on the projectile 400 via anumbilical cord connector 430. The projectile connector 440 includes oneor more contact elements, such as contact elements 100 and 200 discussedabove, that can provide direct-contact and wireless communication. Theumbilical connection to the projectile 400 can be used to downloadcritical data from the pre-launch controller 410 before launch as ameans of initializing missile systems and providing most recent targetdata. More specifically, electrical signals sent from the pre-launchcontroller 410 are transferred to a data processor 480 on the projectile400 via one or more contact elements 100/200 of the projectile connector440.

After launch, as shown in FIG. 18A, communication to the projectile 400is conducted from a transmitting device 450, which can optionally beincluded in the same system as the pre-launch controller 410. A signal460 emitted from the transmitting device 450 is picked up by the contactelements 100/200 of the projectile connector 440 and passed on to areceiver 470. The receiver 470 conditions the picked-up signal accordingto known methods, converting it into electrical signals for use by thedata processor 480. Such communication after launch can be useful forin-flight control of the projectile 400, for example, to alter targetdata.

Prior missiles have an umbilical connector for pre-launch (directcontact) communications and an omni or near omni-directional antenna forpost-launch (wireless) communications. These antenna dominate regions ofthe missile body, absorbing valuable real estate, weight, and costdedicated to proper operation of the antenna and associated receiverelectronics. The projectile 400, on the other hand, makes use of theprojectile connector 440 for both direct-contact and wirelesscommunications, thus eliminating the need for an additional antennamounted to the missile body. In addition, compared to prior missiles,the performance of the projectile 400 is enhanced due to the use of anaft looking antenna that is highly directional, instead of an omni ornear omni-directional antenna on the missile body, which is lessdirectional and therefore requires the use of guard channels, which inturn require additional components. Also, the use of the projectileconnector 440 adds an element of stealthiness to the capabilities of theprojectile 400, since the projectile connector 440 can have the sameexterior appearance as a standard prior connector so that a visualinspection of the projectile 400 would be less likely to reveal thepresence of wireless capabilities.

Other applications where a dual use connector (i.e., direct contact andwireless) can be of use include rockets, satellites, and space vehicles,especially where there are space/weight limitations.

Although the present invention has been fully described by way ofpreferred embodiments, one skilled in the art will appreciate that otherembodiments and methods are possible without departing from the spiritand scope of the present invention.

1. A projectile comprising: a combination antenna-conductor connectorhaving a contact element for mating with a pin element of an opposingconnector in order to transfer electrical signals from the pin elementand for serving as a waveguide for receiving wireless communicationsignals in response to the pin element being removed from the contactelement; a receiver in communication with the contact element forconverting the received wireless communication signals into datasignals; a data processor in communication with the contact element forreceiving from the contact element the electrical signals transferredfrom the pin element.
 2. A projectile according to claim 1, wherein thecontact element is shaped so as to convert circular mode electromagneticwaves entering the therein into where λ_(c) is a lower dominant modecutoff wavelength of an operating frequency of the contact element and kis a constant associated with an operating mode of the contact element.3. A projectile according to claim 1, wherein the contact elementincludes an opening for receiving the pin element and a back wall andwherein the contact element includes a contacting section that iselectrically conductive and extends from the opening towards the backwall.
 4. A projectile according to claim 3, wherein the contact elementincludes a pickup section that is electrically conductive and extendsfrom the back wall towards the opening.
 5. A projectile according toclaim 4, wherein the surface contact element includes an insulatingsection between the contacting section and the pickup section forelectrically isolating the contacting section and the pickup sectionfrom each other.
 6. A projectile according to claim 4, including apickup element extending from the pickup section of the contact element.7. A projectile according to claim 6, wherein a distance d between thepickup element and the back wall satisfies the following relationship:$d = {{\frac{1}{4}\lambda_{g}} = {\frac{1}{4}\sqrt{\frac{\lambda_{o}}{( {1 - {\lambda_{o}/\lambda_{c}}} )^{2}}}}}$where λ_(g) is a wavelength of an operating frequency of the contactelement, λ_(c) is a lower dominant mode cutoff wavelength of theoperating frequency, and λ_(o) is a wavelength of the operatingfrequency in free space.
 8. A projectile according to claim 1, whereinthe opening in the contact element is circular and has a radius r thatsatisfies the following equation: $r = \frac{\lambda_{c}}{k}$ wavelengthof the operating frequency in free space.
 9. A projectile control systemcomprising: a projectile having a projectile connector that includes acontact element; a pre-launch controller for communicating with theprojectile prior to a launch of the projectile; an umbilical cord forelectrically connecting the contact element of the connector to thepre-launch controller; a transmitting device for wirelesslycommunicating with the projectile via the contact element of theconnector after the launch of the projectile.
 10. A projectile controlsystem according to claim 9, wherein the contact element is shaped so asto convert circular mode electromagnetic waves entering the therein intorectangular mode waves.
 11. A projectile control system according toclaim 9, wherein the contact element includes an opening for receivingat least one pin of the umbilical cord and a back wall and wherein thecontact element includes a contacting section that is electricallyconductive and extends from the opening towards the back wall.
 12. Aprojectile control system according to claim 11, wherein the contactelement includes a pickup section that is electrically conductive andextends from the back wall towards the opening.
 13. A projectile controlsystem according to claim 12, wherein the contact element includes aninsulating section between the contacting section and the pickup sectionfor electrically isolating the contacting section and the pickup sectionfrom each other.
 14. A projectile control system according to claim 12,including a pickup element extending from the pickup section of thecontact element.
 15. A projectile control system according to claim 14,wherein a distance d between the pickup element and the back wallsatisfies the following relationship:$d = {{\frac{1}{4}\lambda_{g}} = {\frac{1}{4}\sqrt{\frac{\lambda_{o}}{( {1 - {\lambda_{o}/\lambda_{c}}} )^{2}}}}}$where λ_(g) is a wavelength of an operating frequency of the contactelement, λ_(c) is a lower dominant mode cutoff wavelength of theoperating frequency, and λ_(o) is a rectangular mode waves.
 16. Aprojectile control system according to claim 11, wherein the opening inthe contact element is circular and has a radius r that satisfies thefollowing equation: $r = \frac{\lambda_{c}}{k}$ where λ_(c) is a lowerdominant mode cutoff wavelength of an operating frequency of the contactelement and k is a constant associated with an operating mode of thecontact element.